Send back "comm_close" to unidentified/closed communications

comm/base_comm.py

@@ -290,6 +290,21 @@ def comm_msg(self, stream: ZMQStream, ident: str, msg: MessageType) -> None: #
  comm_id = content["comm_id"]
  comm = self.get_comm(comm_id)
  if comm is None:
+ try:
+ from comm import create_comm
+
+ closed_comm = create_comm(
+ comm_id=comm_id,
+ primary=False,
+ target_name=None,
+ )
+ closed_comm.close()
+ except Exception:
+ logger.error(
+ """Could not send comm_close for a closed comm to reply
+ for incoming communication""",
+ exc_info=True,
+ )
  return
 
  try: